Lowell Observatory finds a new solar-system body

Hubble initially marked three suspected novae on the image; later comparisons revealed one was variable.

The 100-inch telescope recorded faint points in Andromeda that could be compared across nights.

The photographic plate later helped establish that Andromeda lies outside the Milky Way; this conclusion was later, not on the exposure date.

Clyde Tombaugh found a moving point in the photographic plates he had been comparing.

By comparing images of the same star field, Tombaugh detected the movement of the object later named Pluto.

The object initially joined the planetary list and was reclassified as a dwarf planet many decades afterward.

The Soviet Union launched the first artificial Earth satellite from a spaceport in the Kazakh Soviet Republic.

Sputnik 1 began transmitting radio beeps as it orbited Earth, opening new possibilities for tracking a satellite.

Radio signals from Sputnik could be received outside the launch program, making the orbit publicly observable.

The successful launch created a new platform for studying Earth and, later, the wider universe.